Motor fuel



M Nov. 13, 1934 UNITED STATES MOTOR FUEL Chester W. Hannnm, Danville, 11]., assignor, by mesne assignments, to Gasoline Antioxidant Company, Wilmington, Del., a corporation of Delaware No Drawing. Application February 18, 1932, Serial No. 593,878

60laims.

This invention relates to improvements in compositions for use as motor fuels and more particularly to motor fuels containing substances which prevent discoloration and the formation of gummy substances therein during storage or use.

Crude motor fuels, particularly gasolines, as produced commercially at the present time consist of extremely complicated mixtures of saturated and unsaturated hydrocarbons. In the simple forms in which they are originally produced in the manufacture of the crude motor fuels, the unsaturated compounds have a high fuel value which renders them particularly desirable constituents of a motor fuel. However, on standing in contact with air and in use, gasolines containing some of these compounds become colored and rapidly form resinous, gummy, insoluble and non-volatile products which are highly objectionable. The colored products give an undesirable color to the motor fuel rendering it practically unsaleable. The resinous, gummy and insoluble products deposit and form coatings on the walls of the containers, the valves and the jets causing sticking of the valves, clog the jets and decrease the emciency of the fuel, in many cases, making it valueless.

By reason of these objectionable products formed by gasolines containing these constituents, they generally have been treated to remove such constituents from the motor fuel before storage or sale thereof, whereby their value has been lowered. At the present time, these constituents are commonly removed by treating the crude motor fuel with sulphuric acid or with fullers earth in a vapor phase method. These processes are expensiveand increase the cost of the fuel. Furthermore, these processes fail to completely remove the objectionable constituents.

The failure of such removal processes to completely remove the obiectionably acting constituents from motor fuels and prevent gum formation has caused the development of stabilizers and gum inhibitors. Stabilizers and gum inhibitors are compounds which are added to motor fuels to prevent discoloration and the formation of gum in the fuels. The gum inhibitors, which have been developed up to the present time, do not operate as efllciently as desired and require the addition of relatively large quantities thereof to the fuels. They are, however, only very slightly soluble in the motor fuels which renders it diflicult to add the desired quantities. Furthermore some of these inhibitors give an objectionable color to the fuel. Forexample, p-amino phenol precipitates badly from gasoline and colors it an intense red. I

My invention has for an object the production of a motor fuel containing a small amount of gum inhibitor. kfurther object is to incorporate a substance into a motor fuel which substance will make it possible to employ, as a fuel for internal combustion engines, liquid hydrocarbons; such as gasoline, that contain larger amounts of 'unsaturated hydrocarbons. A still further object is to enable such improved fuels to be produced at a lower cost than the fuels at present on the market. Further objects are to produce a new composition of matter and to advance theart. Other and further objects will appear from the following detailed description of my invention.

My present invention is based upon my discovery that certain substituted amino phenols are powerful stabilizers and gum inhibitors for motor fuels such as gasoline. I have found that, when the hydrogen atoms of the amino group of an amino phenol are replaced by a hydrocarbon group, the resulting compound has increased gum inhibiting properties and is markedly more soluble in solvents of low dielectric constant such as benzol and gasoline. Also, thesenew compounds have but little or no tendency to discolor on storage or exposure to light or to precipitate from the motor fuel and do not color such fuel in an objectionable manner.

"The subject matter ofmy present invention comprises motor fuels such as gasoline containing small amounts of gum inhibitors which consist of amino phenols in which both hydrogens of the amino group have been replaced by a hydrocarbon group including an aliphatic carbon atom joined directly to the nitrogen by means -of a. double bond. These compounds have the type formula: V

HORN=O phenol, i-benzylidene amino phenol, 4- (m-nitro I benzylidene) amine phenol, 4-(o-chlorbenzylidene) amino phenol, 2-benzylidene amino phenol, 4-cinnamylidene amino phenol.

Only very minute quantities on the order of 0.005% of these compounds need be added to most motor fuels to be effective. However, more or less than these amounts may be employed as desired. The nature and amount of the unsaturated compounds and the preformed gum present in the motor fuel to be treated will determine to some extent the amount of inhibitor to be used. Fuels containing, preformed gum usually require the addition of larger amounts of inhibitor due to the accelerating action of the gum.

Any desired method of adding the inhibitor may be employed. Satisfactory methods are (1) dissolving the compound in a solvent such as methanol or benzol and then dissolving the solution in the motor fuel and (2) allowing the motor fuel to percolate through a mass of the compound to dissolve the compound directly from the mass thereof.

In order to clearly point out the invention motor fuels containing gum inhibitors of the present invention were tested according to the oxygen gum test proposed by Voorhees and Essinger in their paper entitled Importance and significance of gum in gasoline appearing in Processes of the American Petroleum Institute, (1929) volume 10, section II, page 169. This test comprises heating 25 cc. of gasoline to 100 C. under an oxygen atmosphere in a glass rubber stoppered flask on a boiling water bath, continuing the heating to beyond the induction period, then removing the volatile matter in a steam atmosphere and directly weighing the gum formed. Gasolines when heated as described for a sufficient length of time, begin to form gum. The length of time for which such compounds must be heated before gum begins to form is known as the induction period. Gasoline containing unsaturated compounds rapidly forms large quantities of gum on being heated beyond such period. A gum inhibitor extends the induction period and tends to decrease the rate of gum formation and the amount thereof on heating a motor fuel containing the inhibitor beyond the induction period.

The gum inhibitors of my invention have these desirable characteristics to a marked degree as will be appreciated from a consideration of the following examples. I

Example 1.+-A gum-free unsaturated gasoline containing 0.003% by weight of 4-benzylidene amino-phenol was heated for 4 hours under the above described conditions of the oxygen gum test. Simultaneously, 25 cc. of thesame gasoline containing no stabilizer or gum inhibitor was subjected to identical treatment. As a result of such treatment 41 mg. of gum per 25 cc. of gasoline was formed in the gasoline containing the gum inhibitor while 112 mg. of gum per 25 cc. of gasoline was formed in the gasoline which contained no inhibitor.

Example 2.A gum-free unsaturatedgasoline amino phenol was treated similarly to that of Example 1. This gasoline formed 42 mg. of gum per 25 cc. of gasoline while the uninhibited control sample formed 256 mg. of gum per 25 cc.

Example 4.-An unsaturated gasolinacontaining 0.005% by weight of 4-(m-nitrobenzylidene) amino phenol was similarly treated with the formation of 68 mg. of gum per 25 cc. of gasoline. The uninhibited control sample in this case formed 256 mg. of gum per 25 cc. of gasoline.

Example 5.--An unsaturated gasoline containing 0.005% by weight of 4-butylidene amino phenol was similarly heated and formed '76 mg. of gum per 25 cc. of gasoline. The uninhibited control sample in this instance formed 188 mg.-

mentioned are the following: 4-ethylidene amino phenol, 2-ethylidene amino phenol, 2-butylidene amino phenol, 4-propylidene amino phenol, 4- tolu benzylidene amino phenol, 4-B-phenyl ethylideneamino phenol. The isomeric forms of these compounds as well as their homologues and derivatives are deserving of attention.

I have found that the compounds forming the subject matter of my invention are 7 excellent stabilizers and gum inhibitors even when employed in the small amounts mentioned. They effectively prevent discoloration and the formation of gum by the constituents of gasolines which have been less completely refined and contain larger amounts of unsaturated compounds than the motor fuels at present on the market. Hence, such less completely refined motor fuels retaining the fuel value of the unsaturated compounds may be made available to the consumer. Such improved fuels will also be made available at lower cost due to the elimination of at least part of the usually necessary refining processes. The addition of the extremely small amounts of the inhibitors will have but little effect on the cost of the gasoline.

These inhibitors are readily soluble in gasoline and the like, do not readily precipitate from their solutions and are therefore distinguishable in their action from those at present on the market. These compounds used in accordance with the invention do not objectionably color the gasoline.

While my invention has been described in some detail many modifications of the same will be readily apparent to those skilled in the art without departing from the spirit of my invention. Accordingly, my invention is to be limited only by the scope of the appended claims construed as broadly as is permissible in view of the prior art.

I claim:

' 1. A motor fuel comprising cracked hydrocarbon distillates normally tending to deteriorate and develop gummy substances on storage and having incorporated therein, in an amount suilicient to inhibit the formation of such gummy substances an organic compound having the formula:

wherein R represents a radical of the benzene type.

2. The method of preserving cracked gasoline which normally tends to deteriorate and develop gums on storage by incorporating therein, in an amount sufficient. to substantially retard such deterioration and gum formation, an organic compound having the formula:

QNE-OHR wherein R represents a phenyl radical.

3. A motor fuel comprising cracked gasoline normally tending to form gummy substances on storage and having incorporated therein, in an amount sufficient to inhibit such formation of gummy substances, a benzylidene aminophenol.

4. A motor fuel comprising cracked gasoline normally tending to deteriorate and form gum on storage and having incorporated therein, in

CHESTER 'w. \HANNUM. 

